Placental pathological findings in triplet pregnancies conceived through assisted reproductive technology: a study of...

The aim of this study was to determine whether triplet placentas conceived via assisted reproductive technology (ART) present more abnormalities than those conceived in vivo.

We conducted a single-centre, retrospective, case-control study including all triplet pregnancies with placental examination at a Pathology Department. The control group consisted of in vivo-conceived triplets (natural conception and artificial insemination), and the case group included ART-conceived triplets (in vitro fertilization and intracytoplasmic sperm injection). Univariate and multivariate analyses were performed.

A total of 98 triplet pregnancies were included: 33 in the in vivo group and 65 in the ART group. Monochorionic triamniotic placentation was more frequent in the in vivo group (p = 0.02), while dichorionic triamniotic placentation predominated in the ART group (p = 0.03). Primiparity was more common in the ART group (p = 0.02). Higher rates of fetal growth restriction (p = 0.03), neonatal death (p = 0.04), and NICU admission (p = 0.04) were also observed in this group. ART placentas showed lower weight (p = 0.03), and more frequent marginal (p = 0.01) and velamentous (p < 0.01) cord insertions. Histologically, higher rates of chronic villitis (p = 0.02), accelerated villous maturation (p = 0.01), intervillous fibrin deposition (p = 0.01), and chorangiomas (p = 0.04) were found in the ART group. In contrast, placental edema (p = 0.01) and nucleated red blood cells (p = 0.02) were more common in the in vivo group.

ART-conceived triplets are associated with more placental abnormalities, which may underlie the higher rates of adverse pregnancy outcomes. Further research into immunological and vascular mechanisms could improve understanding and management of these pregnancies.